Manually Adjusting the Screen Brightness

Manually adjusting the screen’s
brightness enables you to maintain a certain level of brightness,
regardless of the current lighting conditions. For example, Windows
Phone 8 is designed to automatically dim the screen when you are using
the phone in a dark area and to brighten the screen when you are in a
bright area. If you prefer to use a consistent level of brightness, go
to the Settings screen and follow these steps: